mmc: core: Add support for HS400 re-tuning
HS400 re-tuning must be done in HS200 mode. Add
the ability to switch from HS400 mode to HS200
mode before re-tuning and switch back to HS400
after re-tuning.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index fd41b28..a802863 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1092,6 +1092,94 @@
return 0;
}
+int mmc_hs200_to_hs400(struct mmc_card *card)
+{
+ return mmc_select_hs400(card);
+}
+
+/* Caller must hold re-tuning */
+static int mmc_switch_status(struct mmc_card *card)
+{
+ u32 status;
+ int err;
+
+ err = mmc_send_status(card, &status);
+ if (err)
+ return err;
+
+ return mmc_switch_status_error(card->host, status);
+}
+
+int mmc_hs400_to_hs200(struct mmc_card *card)
+{
+ struct mmc_host *host = card->host;
+ bool send_status = true;
+ unsigned int max_dtr;
+ int err;
+
+ if (host->caps & MMC_CAP_WAIT_WHILE_BUSY)
+ send_status = false;
+
+ /* Reduce frequency to HS */
+ max_dtr = card->ext_csd.hs_max_dtr;
+ mmc_set_clock(host, max_dtr);
+
+ /* Switch HS400 to HS DDR */
+ err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
+ EXT_CSD_TIMING_HS, card->ext_csd.generic_cmd6_time,
+ true, send_status, true);
+ if (err)
+ goto out_err;
+
+ mmc_set_timing(host, MMC_TIMING_MMC_DDR52);
+
+ if (!send_status) {
+ err = mmc_switch_status(card);
+ if (err)
+ goto out_err;
+ }
+
+ /* Switch HS DDR to HS */
+ err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BUS_WIDTH,
+ EXT_CSD_BUS_WIDTH_8, card->ext_csd.generic_cmd6_time,
+ true, send_status, true);
+ if (err)
+ goto out_err;
+
+ mmc_set_timing(host, MMC_TIMING_MMC_HS);
+
+ if (!send_status) {
+ err = mmc_switch_status(card);
+ if (err)
+ goto out_err;
+ }
+
+ /* Switch HS to HS200 */
+ err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
+ EXT_CSD_TIMING_HS200,
+ card->ext_csd.generic_cmd6_time, true, send_status,
+ true);
+ if (err)
+ goto out_err;
+
+ mmc_set_timing(host, MMC_TIMING_MMC_HS200);
+
+ if (!send_status) {
+ err = mmc_switch_status(card);
+ if (err)
+ goto out_err;
+ }
+
+ mmc_set_bus_speed(card);
+
+ return 0;
+
+out_err:
+ pr_err("%s: %s failed, error %d\n", mmc_hostname(card->host),
+ __func__, err);
+ return err;
+}
+
/*
* For device supporting HS200 mode, the following sequence
* should be done before executing the tuning process.